EXPERIMENTAL GLOBE RUPTURE AFTER EXCIMER-LASER PHOTOREFRACTIVE KERATECTOMY

Objective: To assess corneal weakening after photorefractive keratectomy. Methods: Photorefractive keratectomy was performed in 16 human eye-bank eyes by means of a 193-nm excimer laser (range, 6 to 54 diopters [D]). Porcine eyes underwent either photorefractive keratectomy procedures (range, 30 to 93 D) with a 5-mm beam diameter or deep 5-mm piano disc ablations. Intraocular pressure was increased gradually with the use of nitrogen gas until the globe ruptured. Results: Human eyes with less than 42 D of correction ruptured at the limbus or behind the insertions of the extraocular muscles. Two eyes showed initial leakage at the 42-D ablation site. Ablations greater than 46 D entered the anterior chamber during treatment. One porcine eye ruptured at the ablation site after a 42-D treatment. Other eyes ruptured at the equator with treatments up to 78 D. Conclusion: Excimer laser photorefractive keratectomy does not weaken the cornea after degrees of ablation commonly used in the clinical setting.